Table of Contents
Why is salinity a global problem?
Salinity and water are inextricably linked. This means salinity is affected by climate variability, which can tend towards extremes in New South Wales. Salinity usually occurs with other natural resource problems such as decreasing soil and water quality, erosion and loss of native vegetation.
What is the important problem related to salinity?
Salinity is an important land degradation problem. Soil salinity can be reduced by leaching soluble salts out of soil with excess irrigation water. Soil salinity control involves watertable control and flushing in combination with tile drainage or another form of subsurface drainage.
Why is salinity a problem in Australia?
Salinity has been caused by extensive land clearing in Australia, predominantly for agricultural purposes. Land clearance can also lead to soil erosion and, when it results in a changing water balance, to dryland salinity.
Is salinity abiotic or biotic?
Salinity is an important abiotic factor because the normal functioning of animals depends on the regulation of the water and ions in their internal environment, which is influenced by the water and ions in their external environment (Moyes & Schulte 2006).
Why is salinity bad for plants?
Salinity becomes a problem when enough salts accumulate in the root zone to negatively affect plant growth. Excess salts in the root zone hinder plant roots from withdrawing water from surrounding soil. This lowers the amount of water available to the plant, regardless of the amount of water actually in the root zone.
How salinity is caused?
Primary salinity is caused by natural processes such the accumulation of salt from rainfall over many thousands of years or from the weathering of rocks.
Where is salinity an issue in Australia?
Western Australia contains the majority of land affected by salinity in Australia, with around 70%. Over 2 million hectares are currently affected, and around 4 million hectares of land are currently listed as high risk, and 50% of divertible water is already considered overly saline.
How does salinity affect biotic factors?
Salinity affects production in crops, pastures and trees by interfering with nitrogen uptake, reducing growth and stopping plant reproduction. Some ions (particularly chloride) are toxic to plants and as the concentration of these ions increases, the plant is poisoned and dies.
Is salinity a abiotic factors?
An abiotic factor is a non-living part of an ecosystem that shapes its environment. In a terrestrial ecosystem, examples might include temperature, light, and water. In a marine ecosystem, abiotic factors would include salinity and ocean currents.
How does salinity affect animals?
Organisms can cope with salinity variation in two ways: they can adjust their tissues’ aminoacids concentartion adapting it to the concentration of the water, or keep unchanged their osmotic pressure despite water’s salinity variation; however the level of tolerance is different among species.
How does salinity affect fish?
In larger fish, salinity is also a key factor in controlling growth. Better growth at intermediate salinities (8-20 psu) is very often, but not systematically, correlated to a lower standard metabolic rate. Numerous studies have shown that 20 to >50% of the total fish energy budget are dedicated to osmoregulation.
How do humans affect salinity?
Human activities can cause salinization through the use of salt-rich irrigation water, which can be exacerbated by overexploitation of coastal groundwater aquifers causing seawater intrusion, or due to other inappropriate irrigation practices, and/or poor drainage conditions.
What causes salinity to increase or decrease?
Here the ocean is being diluted so that the salinity is decreased. This may occur in areas of high rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of fresh water by precipitation or runoff.
What conditions would causes more salinity?
Evaporation due to high temperature with low humidity (dry condition) causes more concentration of salt and overall salinity becomes higher. For example, salinity is higher near the tropics than at the equator because both the areas record high rate of evaporation but with dry air over the tropics of Cancer and Capricorn.
What are the sources of salinity?
Primary salinity occurs naturally in soils and waters. Examples of naturally occurring saline areas include salt lakes, salt pans, salt marshes and salt flats. Secondary salinity is salting that results from human activities, usually land development and agriculture.
What does high salinity mean?
High salinity makes water denser. This is because there is more salt packed into the water. High temperature makes water less dense. As water gets warmer, its molecules spread out, so it becomes less dense. As it gets colder, it becomes denser. Most chemicals get denser when they turn from a liquid to a solid,…